Self-contained benthonic blowout prevention control apparatus and method



Feb. 24, 1970 P. R. ROWLEY 3,496,999

SELF-CONTAINED BENTHONIC BLOWOUT PREVENTION CONTROL APPARATUS AND METHODFiled Dec. 26, 1967 INVENTOR. PAUL l3. ROM/LE) BYMM ATTORNEK UnitedStates Patent SELF-CONTAINED BENTHONIC BLOWOUT PRE- VENTION CONTROLAPPARATUS AND METHOD Paul Robert Rowley, Long Beach, Calif., assignor toAt lantic Richfield Company, Philadelphia, Pa., a corporation ofPennsylvania Filed Dec. 26, 1967, Ser. No. 699,001 Int. Cl. E21b 7/12US. Cl. 166.5 4 Claims ABSTRACT OF THE DISCLOSURE This applicationrelates to the control of fluid operated equipment on the ocean floorduring drilling operations conducted from a floating vessel through ariser extending between the ocean floor and the vessel. Hydraulic fluidis stored in a benthos reservoir, from which it is pumped to a group ofaccumulators by a motor pump assembly. From the accumulators, thepressurized hydraulic fluid is piped through a valve and manifoldassembly to the individual components of the blowout preventer stack.The valve and manifold assembly consists of a series of electricallyactuated valves which control the fluid applied to the individualblowout preventer units, and which are electrically controlled from thevessel to provide means for controlling the blowout preventers from thevessel. The reservoir, accumulators, and motor pump assembly are eacharranged annularly around the lower end of the riser adjacent theblowout preventer stack.

Ocean floor drilling equipment, such as blowout preventers, latchingmechanisms, etc., are normally controlled by fluid pressure appliedthrough hoses extending between the vessel and the individual blowoutpreventer units. Such hoses are shown, for example, in US. Patent No.3,236,- 308 to Leake. Relatively high fluid pressure is normallymaintained in these hoses and they frequently fail under Working andflexure conditions at such pressures. Replacement of the hoses to theindividual blowout preventers is costly in that it is time consuming andrequires the use of divers, or in deep water installations may requireretrieval of the blowout prevention equipment to the vessel forreplacement of the hoses. Having a multiplicity of hoses running fromthe vessel to the ocean floor increases the incidence of failure andalso gives rise to hose entangling which often requires the services ofa diver for untanglement. The elimination of all high pressure hydraulichoses from the vessel to the ocean floor equipment is desirable to avoidthe aforementioned complications. Accordingly, it is considereddesirable to provide a system for controlling benthos blowout preventionequipment by supplying only electrical energy to the benthos well headequipment.

It is an object of my present invention to provide a system for drillingfrom a floating vessel with the blowout prevention equipment positionedon the ocean floor without the need for high pressure, hydraulic controllines extending between the vessel and the benthos equipment.

It is also an object of my present invention to provide a system fordrilling a benthos well from a floating vessel with the blowoutprevention hydraulic control equipment located on the ocean floor, butoperated remotely from the vessel.

It is a further object of my present invention to provide a system fordrilling an underwater well from a 3,496,999 Patented F eb. 24, 1970floating drilling vessel, with the hydraulic control fluid stored anddistributed to the individual blowout preventers from equipmentpositioned on the lower end of the riser pipe proximate the ocean floor.

Other objects and a more complete understanding of my present inventionwill be appreciated by reference to the drawing wherein an offshoredrilling arrangement is shown diagrammatically with the floatingdrilling vessel arranged over the benthos well.

Referring more particularly to the drawings, a well 10 is drilled in awater covered formation 12 from a floating drilling vessel 14 in theconventional manner and a blowout preventer stack 16 installed at theocean bottom on the lower end of a riser 18 which extends from thevessel to the well opening. The blowout prevention equipment, referredto generally as 16, is conventional equipment which may be fluid orhydraulically operated through control hoses extending from a valve andmanifold assembly 20 to the individual blowout preventers 22 and 24. Thevalve and manifold assembly receives hydraulic fluid from a series ofannularly spaced accumulators 26 which are manifolded together andreceive pressurized hydraulic fluid from motor-pump assembly 27 which isarranged annularly around sub 29. The blowout preventers 22 and 24 areindividually controlled by an electrical cable 32 extending between thevalve and manifold assembly and the vessel 14 and containing suflicientwires to serve each of the blowout preventer units. In addition to theblowout preventers, the valve and manifold assembly may also be used toregulate the hydraulic control fluid to other benthos well headequipment, e.g. kill line valve 50.

The accumulators 26 receive pressurized hydraulic fluid from water pumpassembly 27. The motor-pump assembly 27, shown in cutaway view, maycontain several vertically oriented motors and pumps and a pressureswitch in an oil-filled annular space between the riser sub 29 and anouter casing 33. The pumps within the motor-pump assembly 27 are smallbut relatively high pressure pumps driven by electrical motors whichreceive electrical energy through the electrical cable 35 which extendsto the vessel with electrical cable 32. The motor pump assembly has twolines, one line 37 to the reservoir 31, and line 57 leading to the oilside of the accumulators. The annular reservoir 31 may be of anysuitable design such as a sleeve-type bladder 39 within the annularspace between reservoir casing 41 and the riser sub 43. A line 45provides fluid communication between the valve and manifold assembly 20and the reservoir 31 to release the hydraulic pressure from the blowoutpreventer units.

As a typical manner of installing and operating the system of thepresent invention, the surface pipe 34 may first be run and cemented inany conventional manner. Normally a base 36 is lowered on the drillstring (not shown) and set on the ocean bottom 12 and the well drilledsufficiently to receive the surface pipe 34. The surface pipe is thenguided into the hole on the guidelines 38 with a bit guide (not shown)and hung with a landing mandrel 35 attached to the upper end of thesurface pipe, either on the base 38 or a conductor pipe, and the surfacepipe is then cemented to the formation 12. The surface pipe may be runinto the hole on a conventional safety release joint 42 which preferablyis internally actuatable.

The blowout preventer stack 16 is attached to the lower end of the riser18 with a conventional safety release joint 40 and run until the lowerend of the blowout preventer stack is latched to the upper end of thesurface casing mandrel 35 with safety release joint tool 42. Drilling isconducted by operating through the riser 18, a drill pipe (not shown)having a bit on its lower end. Conventional rotary equipment (not shown)is positioned on the vessel for rotating the drill pipe.

The blowout preventer stack 16 as shown includes a double Shaffer gate24 and a Hydril bag-type blowout preventer 22. Each of the units 22 and24 are hydraulically controlled through their control hoses 22a and 24a,respectively, which interconnect these units with the valve and manifoldassembly 20.

A kill line valve 50 is shown on the casing of the blowout preventer 24for injection of weighting mud through a kill line for killing the wellin the event of a high pressure condition below.

The valve and manifold assembly 20 consists of a group of remotelyactuable valves 46 which control the flow of hydraulic pressure from theaccumulators 26 to the hydraulically controlled units 22 and 24. Hencewhen it is desired to close the blowout preventer 22 to seal around thedrill pipe, a valve 46 which is shown in the cutaway portion of valveand manifold assembly 20, is actuated from the vessel through electricalconductors in cable 32, to admit, for example, hydraulic pressure fromthe accumulators 26 to the Hydril unit 22 to close the Hydril rubberseal element (not shown) around the drill pipe in the conventionalmanner. The valve and manifold assembly 20 contains sufficient valves 46to control each of the hydraulically operated units in the blowoutpreventer stack 16. Preferably the valves are positioned in an oilfilledannular space within the external protective casing or cylinder 48. Inthe embodiment shown, the valve and manifold assembly 20 has eighthydraulic lines or hoses connected thereto, two each for the operationof units 22 and 24 and the kill line 50a and one line connected tohydraulic fluid reservoir, and a line 54 interconnecting the valve andmanifold assembly with the annular accumulator manifold 56.

The accumulator assembly comprises sufl'icient accumulators 26 necessaryto store the amount of energy required. An accumulator may be aconventional accumulator which is essentially a high-pressure vesselwith a diaphragm inside which separates hydraulic fluid from a highpressure gas, the purpose of the accumulator being merely to storeenergy in a compressed gas. The expansion of the gas forces hydraulicfluid through the control lines when the switch valves 46 in the valveand manifold assembly 20 are opened. As shown in the drawing, threeaccumulators are symmetrically spaced around a riser sub and manifoldedtogether at the outlet 56 and inlet manifold 58. The annular manifoldsmay serve as connecting means which are aflixed to the riser pipe sub 60in any convenient manner, as with a bracket on a frame supporting theannular manifold. The line 54 between the accumulators and the valve andmanifold assembly may be a solid pipe. A flexible charging line 57conveys a high pressure fluid from the motor pump assembly to themanifolded accumulators 26.

The accumulator assembly, the motor pump assembly 27, the reservoir 31,and each of the blowout preventer elements 22 and 24 may be consideredpart of the riser in that they have a central opening which iscontiguous with the central opening of the riser pipe 18. These unitsare arranged on special subs, for example, the accumulator sub 60 whichis flanged at 64 and 66 above and below, respectively.

Hence, it can be readily seen by my invention that only electricalenergy is provided to the ocean floor drilling equipment, thuseliminating hydraulic connections between the vessel and the ocean floorand eliminating a source of diver expense.

Electrical controls on the boat permit remote operation of the valvesand valve and manifold assembly 20 and the motor pump assembly 27 topermit remote control of the various hydraulically controlled units 22,24, and kill line valve 50.

While my invention is described with reference to an electrical devicewhich would normally utilize a solenoid to actuate the valves 46 in theassembly 20, it is also within the scope of my present invention toemploy electronic equipment which would eliminate the need for theelectrical cable 32.

While my present invention has been described herein with respect tocertain specific apparatus, it is to be understood that variousmodifications in my invention may be made by substitution of equivalentcomponents without departing from the spirit of my invention, and hencemy invention should be afforded the full scope of the appended claims.

I claim:

1. A system for controlling blowout prevention equipment aflixed to thelower end of a riser extending between a formation underlying a body ofwater and a structure proximate the surface of said water, comprising incombination:

(a) an accumulator assembly including a plurality of accumulatorsmanifolded together proximate said blowout prevention equipment,

(b) a hydraulic motor-pump assembly positioned proximate saidaccumulator assembly with a line interconnecting said accumulatorassembly with said motor-pump assembly,

(c) a hydraulic fluid reservoir in fluid communication with saidmotor-pump assembly,

(d) a valve and manifold assembly proximate said blowout preventionequipment arranged and constructed to control the flow of hydraulicfluid from said accumulators to said blowout prevention equipmentthrough hydraulic control valves, said valve and manifold assembly beingin fluid communication with said accumulators and said reservoir, and

(e) means for actuating said valves remotely to control said blowoutprevention equipment from said structure.

2. The apparatus of claim 1 wherein said motor-pump assembly, saidreservoir, said accumulator assembly, and said valve and manifoldassembly are arranged annularly around each riser.

3. The apparatus of claim 1 wherein said valve and manifold assembly isconnected to said blowout prevention equipment to provide for dischargeof hydraulic fluid from said blowout prevention equipment.

4. A system for controlling blowout prevention equipment aflixed to thelower end of a riser extending between a formation underlying a body ofwater and a structure proximate the surface of said water, comprising incombination:

(a) a motor-pump assembly positioned proximate said blowout preventionequipment,

(b) means for supplying electrical energy to said motor-pump assemblyfrom said structure,

(0) a hydraulic fluid reservoir annularly arranged around said riserproximate with said motor-pump assembly and in fluid communicationtherewith,

(d) a series of accumulators arranged proximate said motor-pump assemblyand in fluid communication therewith whereby said motor-pump assemblypumps hydraulic fluid from said reservoir to said accumulators,

(e) means for distributing pressurized hydraulic fluid from saidaccumulators to said blowout prevention equipment, and

(f) means for remotely actuating said blowout prevention equipment fromsaid structure.

(References on following page) 5 6 References Cited 3,219,118 11/1965Lewis 166.6

UNITED STATES PATENTS 3,333,302 8/1967 H by 3064735 11/1962 B er t l 1666 3,339,632 9/1967 L v 1s 1 r J an e a I 3,163,224 12/1964 Haeberet a1166.6 5387 10/1968 et a1 1 166 5 X 3,186,486 6/1965 Rhodes et a1 5CHARLES E. OCONNELL, Primary Examiner 3,199,595 8/1965 Lafitte et a1.166.6

3,21 Hoch Assistant Examiner

